(a) Technical Field of the Invention
The present invention generally relates to fastening devices, and more particularly to a plastic fastening device comprising a bolt, a nut, and at least a washer where the washer contains a saw-toothed plate inside for enhanced reliability.
(b) Description of the Prior Art
Plastic bolts and nuts are provided for applications requiring both fastening and electrical insulation. In addition to its insulating property, the plastic fastening device has a number of advantages such as lightweight and inactivity, in comparison its metallic counterparts. However, plastic bolts and nuts have limited strength and therefore are applied only when light workload is involved. Additionally, under vibration or external force, plastic bolts and nuts may be deformed and become loosed, reducing their applicability significantly.